Obesity is a national epidemic that is widely recognized to be environmental in origin, Primary prevention interventions that address both environmental and individual-level influences on obesity are urgently needed. The primary aim of the proposed study is to evaluate a household-level weight-gain prevention intervention that includes both environmental change and individual-level behavior change components. Four hundred forty households will be recruited and randomized to one of two groups for a 1-year period: 1) household environmental weight-gain prevention program or 2) control program that provides only general behavioral weight control recommendations The primary outcome is household-level change in body weight over the 1-year intervention period. The household environmental weight-gain prevention program includes reduced access to television viewing via a television time-limiting device; reduced household availability of high fat/energy prepackaged foods and less frequent fast food restaurant use; and increased frequency of self-weighing with the provision of a home scale to each household. In addition, the individual-level behavioral change component targets specific eating and exercise behaviors that dovetail with the household environmental changes to promote weight control. The intervention program format consists of 6 monthly face-to-face group meetings, 12 monthly newsletters, 6 encouragement telephone calls, and continuous access to intervention staff via telephone and email. The control group program consists of 12 monthly newsletters that provide general behavioral recommendations for weight control. The primary outcome is household-level percent weight change measured one year following the initiation of treatment. Secondary outcomes are changes in energy intake, physical activity, television viewing time, and frequency of self-weighing. It is hypothesized that intervention households will gain significantly less weight over the 1-year intervention period than households randomized to the control group.